JPH0560232A - Neutral brake device for hydrostatic continuously variable transmission - Google Patents

Abstract

(57) [Summary] [Purpose] The brake is applied in the neutral position of the hydrostatic continuously variable transmission. [Structure] A friction plate type brake mechanism B for applying a braking force is provided on an output shaft 1A of a hydrostatic continuously variable transmission 1.
In order to automatically switch to the operating state at the neutral position and to the non-operating state at the non-neutral position of the hydrostatic continuously variable transmission 1, the neutral biasing to the brake mechanism B and the hydrostatic continuously variable transmission 1 is performed. It is linked to the mechanism A.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrostatic continuously variable transmission.

[0002]

2. Description of the Related Art A hydrostatic continuously variable transmission used as a transmission has a structure in which a stopped state is revealed at a neutral position. Due to the limitation, for example, even if the operating system is set to the neutral position, the hydrostatic continuously variable transmission can be held at the neutral position by the interchange in the linkage mechanism between the operating system and the hydrostatic continuously variable transmission. Sometimes there is not. Therefore, even if the worker intends to set the neutral position, it is often slightly displaced from the neutral position, and it is difficult to obtain the stopped state. Therefore, conventionally, focusing on the fact that the hydrostatic continuously variable transmission utilizes hydraulic pressure without taking any solution in the operation system such as the operation lever, the hydraulic pump of the hydrostatic continuously variable transmission. A valve that bypasses the oil from the hydraulic pump and brings out a neutral state is provided in the hydraulic circuit that connects the hydraulic circuit and the hydraulic motor.

[0003]

With the above construction, it is possible to establish a neutral state in the hydraulic system, and although there are few problems in that respect, since a valve is used,
The cost was inevitably high, and it was difficult to install on low-priced machines. The present invention is to provide a product that can be completely stopped at the neutral position, but that is also cost-effective.

[0004]

A characteristic structure according to the present invention is to provide a friction plate type brake mechanism for exerting a braking force on an output shaft of a hydrostatic continuously variable transmission, wherein the brake mechanism is the hydrostatic type In order to automatically switch to the operating state at the neutral position of the step-variable transmission and to the non-operating state at the non-neutral position of the hydrostatic stepless transmission, the brake mechanism and the hydrostatic stepless transmission are automatically switched. The point is that the neutral switching mechanism is linked, and the action and effect are as follows.

[0005]

In other words, by providing the brake mechanism that mechanically applies the braking force, the neutral switching mechanism does not have to be set to the complete neutral position, and the neutral switching mechanism does not have the hydrostatic continuously variable mechanism. When it is in the position corresponding to the neutral position of the transmission, it is automatically stopped by the brake mechanism,
The neutral state is maintained.

[0006]

Therefore, since the stopped state can be reliably obtained, and only the friction plate type brake mechanism is provided, the cost can be saved compared with the valve. Moreover, since the drive torque of the hydrostatic continuously variable transmission itself is not large in the vicinity of the neutral position, a compact brake mechanism may be used. Further, since the brake mechanism is of the friction plate type, the stroke required for switching between the brake operating state and the non-operating state can be shortened, the braking force can be switched on and off instantaneously, and a quick switching operation can be performed.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a hydrostatic continuously variable transmission 1
The trunnion shaft 2 that rotates integrally with the gear shifting swash plate on the lateral side of the
And a gearshift arm 3 for rotating the trunnion shaft 2 to rotate around the axis of the trunnion shaft 2 so as to shift gears. The gearshift arm 3 is provided with a forward / reverse gearshift pedal 4 for gearshift operation. The shift operation system is configured in cooperation with each other.
On the lower surface of the speed change arm 3, a cam surface 3A that is recessed upward toward the middle portion is formed, a cam follower 5A that moves along the cam surface 3A is attached to the swing arm 5, and the swing arm 5 is biased upward. Then, the cam follower 5A and the cam surface 3A constitute a neutral urging mechanism A for the speed change arm 3. The shift operation system and the neutral biasing mechanism A are referred to as a neutral switching mechanism for the hydrostatic continuously variable transmission 1.

Next, a neutral brake device for applying a brake at the neutral position of the hydrostatic continuously variable transmission 1 will be described. As shown in FIGS. 1 to 3, an output shaft 1A is provided so as to project from the hydrostatic continuously variable transmission 1, and a receiving plate 6 for receiving a friction plate 8 described later and a holder 7 are provided outside the receiving plate 6. Then, the receiving plate 6 and the holder 7 are bolted to the side surface of the hydrostatic continuously variable transmission 1 in the overlapping state and surrounding the output shaft 1A. A friction plate 8 that exerts a braking force is fitted to the output shaft 1A while rotating integrally with the output shaft 1A, and the friction plate 8 is inserted between the receiving plate 6 and the holder 7. A direction in which the piston body 9 that is pressed against the friction plate 8 is movably inserted into the cylindrical portion 7A of the holder 7 and the piston body 9 is pressed against the friction plate 8 by the spring 10 provided in the cylindrical portion 7A. Then, the brake mechanism B of the hydrostatic continuously variable transmission 1 is formed.

The linkage between the brake mechanism B and the neutral switching mechanism will be described. As shown in FIGS. 1 to 3, a horizontal rotation shaft 11 is installed above the holder 7, and a first boss 12 is integrally rotatably mounted on the horizontal rotation shaft 11 so that a pair of left and right parts can be attached to the first boss 12. Arms 13, 13
Extend. On the other hand, the other end of the piston body 9 held by the holder 7 on the side opposite to the friction plate 8 side is connected to the cylindrical portion 7A.
The pins 14 and 14 projecting outward in the left-right direction are provided on the outer end of the piston body 9 while protruding further outward.
4, 14 are arranged close to the tips of the arms 13, 13. Cam surfaces 13A and 13A with the corners cut off are formed at the tips of the arms 13 and 13, and the cam surfaces 13A and 13A are cut off.
When A is brought into contact with the pins 14 and 14 to enable the pressure braking action of the piston body 9 on the friction plate 8, and when the tip end surface of the arm 13 not forming the cam surface 13A is brought into contact with the pin 14, The body 9 can be separated from the friction plate 8 so that the brake is not applied. 1st boss 1
2, the second boss 15 is attached to the lateral rotation shaft 11 so as to be integrally rotatable, and the relay arm 16 is extended from the second boss 15. The relay arm 16 and the swing arm of the neutral biasing mechanism A are provided. 5 and 5 are interlocked with each other by a connecting rod 17, and when the swing arm 5 is positioned at the neutral position, the arm 13 is swung downward, and the cam surface 13A is pinned to the pin 14.
The friction plate 8 is pressed by the piston body 9 to bring about a braking action state. From this state, the swing arm 5
When the arm shifts from the neutral position to the gear shift position, the arm 13 swings upward, and the tip end surface of the arm 13 moves the piston body 8 to the spring 10.
It is separated from the friction plate 8 against the urging force of (1) to expose the non-brake state.

[Other Embodiments] In order to switch the braking mechanism B between the operating state and the non-operating state, the gear shift operation system and the braking mechanism B may be linked.

It should be noted that although reference numerals are given in the claims for convenience of comparison with the drawings, the present invention is not limited to the configuration of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a linked state of a neutral switching mechanism and a brake mechanism.

FIG. 2 is a cross-sectional plan view showing a brake mechanism.

FIG. 3 is a vertical sectional rear view showing a brake mechanism.

[Explanation of symbols]

 1 Hydrostatic type continuously variable transmission 1A Output shaft B Brake mechanism

Claims (1)

[Claims] 1. A friction plate type brake mechanism (B) for applying a braking force to an output shaft (1A) of a hydrostatic continuously variable transmission (1), and the brake mechanism (B).
To automatically switch to a working state at the neutral position of the hydrostatic stepless transmission (1) and to a non-working state at the non-neutral position of the hydrostatic stepless transmission (1). A neutral brake device of a hydrostatic continuously variable transmission, wherein the brake mechanism (B) and a neutral switching mechanism for the hydrostatic continuously variable transmission (1) are linked.